<!DOCTYPE html>
<html >
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>返回值</title>
    <script>
        function sum(){
            let he=0;
            for (let i = 0; i < arguments.length; i++) {
                he += arguments[i];  
            }
            return he;
        }
        let res1=sum(1,2,3);
        let res2=sum(13,14);
        console.log(res1,res2);
        function leijia(num = 10){
            let add = 0;
            for(let i=num;i>0;i--){
                add+=i;
            }
            return add;
        }
        let res3=leijia();
        let res4=leijia(100);
        console.log(res3,res4);
    </script>
</head>
<body>
    
</body>
</html>